express emotion vs cry

express emotion is not a noun while cry is a noun.

Word	Noun	Adjective	Verb	Adverb
express emotion	No	No	Yes	No
cry	Yes	No	Yes	No

As verbs, cry is a hyponym of express emotion; that is, cry is a word with a more specific, narrower meaning than express emotion:

Other hyponyms of express emotion include express joy, express mirth, laugh, weep, break, burst, erupt, keen, lament.

express emotion (noun)	cry (noun)
	a loud utterance; often in protest or opposition
	a fit of weeping
	a slogan used to rally support for a cause
	a loud utterance of emotion (especially when inarticulate)
	the characteristic utterance of an animal

express emotion (verb)	cry (verb)
give verbal or other expression to one's feelings	shed tears because of sadness, rage, or pain
	bring into a particular state by crying
	utter a sudden loud cry
	proclaim or announce in public
	utter a characteristic sound
	utter aloud; often with surprise, horror, or joy
	demand immediate action